| The improvement of residents’quality of life is reflected in the improvement of residential thermal and humid environment,which can be divided into three aspects:the second is that residents are more sensitive to temperature and humidity,especially air humidity;the second is the pursuit of health,including residential fresh air system and pollutant filtering and removal system;the third is the tendency to choose concealed and multi-functional thermal and humid treatment equipment.Compared with the traditional room air conditioner,the radiant floor cooling and heating terminal has obvious advantages in energy saving,comfort and beauty,and is widely used in the Yangtze River Basin.However,in the application process,there are also some disadvantages:slow response,unable to undertake the latent heat load,insufficient fresh air,and easy condensation in summer.In order to solve the above problems,combined with the lack of existing research,this paper proposes a multi-functional fresh air unit suitable for the radiation terminal,and analyzes the coupling operation strategy of the two.Firstly,a simulation verification method of comfort zone based on operating temperature is proposed.The indoor comfort zone divided by dry bulb temperature is determined under two different conditions,namely,the operation of fresh air unit and the operation of fresh air unit-radiation terminal coupling system.The feasibility of modifying the radiation terminal operation set point based on the convection terminal operation set point is verified.Secondly,a logical judgment analysis method of thermal and humid demand of air-conditioning equipment is proposed.Starting from the demand side,this paper analyzes the demand proportion of fresh air units in Chongqing and the distribution of（90）ranges during dehumidification and cooling period during dehumidification and cooling period.The functions of fresh air fan are determined:dehumidification and cooling,dehumidification without cooling,ventilation,heating without humidification,and（90）mainly concentrated in the range of 0.4～0.7.Thirdly,a household multi-function fresh air unit is designed and developed,and its performance is analyzed.Firstly,the supply air humidity demand of fresh air unit under different conditions is analyzed and tabulated.Secondly,based on the theoretical analysis and evap-cond simulation,the optimal structure of indoor heat exchanger is determined from three aspects of flow pattern,rib tube structure and pipe diameter.Finally,the numerical simulation analysis is carried out on the off design performance of fresh air unit in different modes,the results show that fresh air unit can meet 98%of the annual dehumidification demand,but the sensible heat load should be shared with the radiation terminal.Then,Energy Plus is used to simulate and analyze the operation performance of the fresh air unit radiation terminal coupling system under the standard energy consumption mode.Firstly,the outdoor hourly temperature and humidity parameter table of in winter and summer design day is established.Secondly,the orthogonal experiment is designed to analyze the influence of supply air temperature,supply water temperature and supply water flow rate on the operation performance of the coupled system,and the optimal operation conditions are determined with the goal of rapid response:in cooling season,supply water flow rate 0.7m/s,supply water temperature 12℃to 16℃,fresh air unit full load operation to 20℃;in heating season,supply water flow rate 0.7m/s,supply water temperature 45℃,fresh air unit full load operation to 20℃.Finally,the operation effects of fresh air unit-radiation terminal system and window ventilation-radiation terminal system are compared and analyzed,and the influence of fresh air unit on the system operation performance is analyzed from the aspects of response time reduction and anti-condensation.Finally,Energy Plus is used to simulate and analyze the more comfortable and energy-saving control strategy of the coupling system.Based on the heat storage and release characteristics of radiant panel and indoor comfort requirements,the early switch on Strategy of coupling system is analyzed from the design day.The functional relationship between the temperature rise/drop rate of different types of residential rooms and the indoor temperature at the start-up time is fitted,which can be extended to the cooling season and heating season,and can be applied to the system control.Combing out the whole year control strategy block diagram of the coupling system,simulating and analyzing the energy saving of the early switch strategy.The results show that compared with the standard energy consumption mode,the early on-off mode can realize the comfort of residents in the room,shorten the operation time of radiation terminal,and save 5.1% of energy in the whole year. |
